I'm now doing the neckband,
pattern reads:
Using back-stitch, join reglan seams, noting that tops of sleeves form part of neckline.
With right side facing and using 2.00 needles, knitt up 79 sts evenly around nec, incl sts from stitch holders and working a button hole as before.

I have lied it out and think i can figure out how it joins, however confused I have looked on this site for back-stitch, and what is reglan seams?